The invention relates to an inertial sensor for the vehicle sensitive triggering of a locking mechanism on a belt retractor, comprising a ball, which is seated in a socket in alignment with a reference plane, and a pivotally mounted sensor lever which rests on the ball, has a free end with a pawl formed thereon and is adapted for cooperation with an externally toothed control disk of the belt retractor.
Such an inertial sensor is adapted to respond to deceleration and acceleration of a vehicle and furthermore, however, to an oblique setting of the vehicle body in relation to the horizontal. The normal reference plane of the socket, in which the ball rests, is horizontal. If the ball is displaced in its socket, it will thrust the sensor lever upward toward the external teeth of the control disk on the belt retractor. To render it possible for the pawl on the free end of the control pawl to engage the teeth of the control disk, it is necessary for the sensor lever to move through a stroke with a predetermined size. Normally the direction of the stroke is in the plane of the control disk, that is to say in a vertical plane.
In many cases however the belt retractor is installed in the vehicle in an inclined setting. Since the resting plane for the ball of the inertial sensor must still be horizontal, the entire inertial sensor is arranged in a correspondingly inclined position in relation to belt retractor. The plane of the control disk is then not vertical but rather inclined in relation to a vertical plane. The direction of the stroke of the sensor lever is in this case not in the plane of the control disk. For the operation of the control pawl to en- gage the teeth of the control disk a larger stroke is required. Such larger stroke of the control pawl however means not only a greater space for the accommodation thereof but also more especially a longer response time until the locking operation is commenced. Such disadvantages can be overcome by a design of the control disk with oblique teeth. For different angles of inclination of the belt retractor it is necessary to provide a correspondingly large number of customized designs of the control disk. This leads to increased manufacturing complexity and higher costs of production.